1. Field of the Invention
The present invention relates to a recording/reproducing cassette of the type equipped with an identification substrate and, more specifically, to a recording/reproducing cassette equipped with a temporary engagement mechanism by means of which the upper and lower shells of the cassette are temporarily engaged with each other, with an identification substrate, which is arranged inside the cassette, being placed therebetween.
2. Description of the Related Art
Recording/reproducing cassettes, for example, magnetic tape cassettes, have been reduced in size and have become endowed with various functions in addition to the recording/reproduction of information on/from the magnetic tape. For example, there are recording/reproducing cassettes equipped with memory that makes it possible to indicate the information recorded on the tape and the length of the tape as well as a function by which it is possible to prevent the recorded information from being inadvertently erased.
FIG. 15 shows an example of a conventional recording/reproducing cassette. In the drawing, a magnetic tape cassette 1 includes: upper and lower shells 2 and 3 having a rectangular configuration; a color plate 4 accommodated in a rear corner of the upper and lower shells 2 and 3 for discriminating write-permit/write-inhibit; reel springs 5 symmetrically arranged on the ceiling of the upper shell 2 for applying a bias to the reels; take-up and supply reels 9 and 10 which are equipped with upper and lower reels 8 and 7, each having a hub around which a magnetic tape 6 is wound; a reel lock portion 11 for preventing the reels from rotating when the cassette is not being used; a safety tab 12 for controlling the writing/reading to/from the magnetic tape 6; an identification substrate 13 for storing information, for example, the kind of information recorded in the cassette; a lid lock 14 for controlling the opening and closing of the lid when the cassette is not being used; a lamp cap 16 for covering the top portion of a lamp hole 15 provided substantially at the center of the front side of the lower shell 3 and serving to detect the end of the tape; and a lid portion 17 for accommodating the magnetic tape 6 placed between the front side walls of the upper and lower shells 2 and 3.
The lid portion 17 comprises a rear lid 18 and a front lid 19 for holding the tape therebetween when the cassette is not being used, a top lid 20 for guiding the entire lid upwards, and a lid spring 21 which constantly biases the entire lid downwards, i.e., so as to close it. The lower shell 3 is equipped with a lock member accommodating portion 22 for accommodating the reel lock portion 11, and a substrate mounting portion 30 in a rear corner of the shells for accommodating the identification substrate 13.
The reel lock portion 11 incorporated in the lock member accommodating portion 22 provided in the rear central section of the lower shell 3, comprises a reel lock slider 23 which is caused to slide inwards when the cassette is not being used and which is caused to slide outwards when the cassette is being used, take-up and supply reel lock claws 24 and 25 mounted on either side of the reel lock slider 23, a slider spring 26 for applying a continuous inward bias on the reel lock slider 23, and a reel lock spring 27 for applying a bias to the take-up and supply reel lock claws 24 and 25 to move away from each other.
As shown in FIGS. 15 and 16, when assembling the reel lock portion 11, constructed as described above, one end of the slider spring 26 is first mounted to the reel lock slider 23, and the other end of the slider spring 26 is fitted from above into a spring engagement portion 28 provided on the rear wall of the lower shell 3, whereby the reel lock portion 11 is mounted to the lock member accommodating portion 22 of the lower shell 3. Then, shafts of the reel lock slider 23 are fitted into the take-up and supply reel lock claws 24 and 25, which are engaged with the reel lock spring 27. The reel lock portion 11, mounted as described above, is guided inwards by the slider spring 26 when the cassette is not being used. When the reel lock portion 11 is thus guided, the forward ends of the reel lock claws 24 and 25 are guided along guide grooves of the accommodating portion 22 and pressed against notched sections of the lower reels 7 of the reels 9 and 10, whereby the rotation of the reels 9 and 10 is prevented.
When the cassette is used, a release bar 29 enters from the bottom side of the cassette, as shown in FIG. 17, and causes the reel lock slider 23 to slide outwards against the bias of the slider spring 26, whereby the lock of the reels 9 and 10 is cancelled.
As shown in FIG. 16, the substrate mounting portion 30 consists of two chambers: a first accommodating portion 31 which is on the right-hand side in FIG. 16 and which is connected to the external connectors of electronic apparatus or the like, and a second accommodating portion 32 which is on the left-hand side and which accommodates the IC portion of the identification substrate 13 which is equipped with IC memory.
The first accommodating portion 31 is provided with a connection window portion 33 consisting of four windows that are open on the outside. At a longitudinal end of the first accommodating portion 31, there is provided an engagement portion 34 which is to be engaged with one end of the identification substrate 13. The second accommodating portion 32 is equipped with an engagement portion 36 which is connected to a reinforcing rib 35 and which is engaged with the other end of the identification substrate 13.
As shown in FIG. 18, like the upper and lower shells 2 and 3, which are formed of a plastic material such as ABS, the identification substrate 13, which is incorporated in the substrate mounting portion 30, is formed of a plastic material such as an epoxy resin or some other engineering plastic (POM or the like). The identification substrate 13 has a narrow and stepped configuration. The wider portion of the substrate constitutes an IC mounting portion 37, and the narrower portion thereof constitutes a terminal portion 38.
An IC chip 39 for storing information on the information recorded in the cassette and the recording/reproducing tape, etc. is mounted substantially at the center of the IC mounting portion 37, and the IC chip 39 is covered with a protective layer 40. The IC chip 39 is connected to the contact terminals of the terminal portion 38.
Four contact terminals are formed in alignment in the terminal portion 38, the terminals consisting of a grounding contact terminal GND, a clock contact terminal SCK, a data contact terminal SDA, and a power source contact terminal VDD, arranged in that order as from the outside.
When incorporating the identification substrate 13, constructed as described above, in the accommodating portion of the lower shell 3, the contact terminals are directed outwards, as shown in FIG. 16, and the longitudinal end portions are engaged with the grooves of the engagement portions 34 and 36 so that the memory mounting portion 37 can be accommodated in the second accommodating portion 32, and inserted from above. By thus inserting, the contact terminals of the terminal portion 38 of the identification substrate 13 equipped with the IC memory 39 are exposed to the exterior through the windows of the connection window portion 33. The memory mounting portion 37 of the substrate 13 is arranged such that it is accommodated in the second accommodating portion 32, and the upper shell 2 is placed from above. That is, the upper and lower end portions of the identification substrate 13 are placed between the upper and lower shells 2 and 3 and secured in position to complete the assembly.
When assembling the magnetic tape cassette, the various parts shown in FIG. 15, for example, the parts constituting the reel lock portion 11, i.e., the slider spring 26, the reel lock spring 27, the reel lock slider 23, and the take-up/supply reel lock claws 24 and 25 and the safety tab 12, the reels 9 and 10 with the tape wound around them, the identification substrate 13, etc. are placed at predetermined positions of the lower shell 3, and, in this condition, the upper shell 2 is placed on the lower shell 3, and pressed against it from above and screwed thereto to complete the assembly.
However, when assembling the above-described conventional magnetic tape cassette, if the various parts, in particular, the parts imparting a biasing force to the slider spring, the reel lock spring, etc. forming the reel lock portion are deviated from the predetermined positions, the mating portions of the upper and lower shells joined together are deviated from each other, or the parts come off, thereby interrupting the assembling process or generating a defective product. More specifically, when the slider spring 26 is in the normal state as shown in FIG. 17, it is accommodated in the spring engagement portion 28 of the lower shell 3 so as to be substantially flush with the upper end surface of the lower shell 3. However, if this slider spring 26A comes off upwards from the spring engagement portion 28 for some reason or other, it pushes the upper shell 2 upwards, with the result that the mating surfaces of the upper and lower shells joined together are deviated from each other, the mounted parts coming off, positional deviation, etc. being generated.
Thus, when the upper and lower shells are joined together with the various parts mounted therein, it is important that no accommodated parts are allowed to be detached or from come off. Further, the mating parts of the upper and lower shells should not be deviated from each other.